Method and apparatus for applying viscous or paste material onto a substrate

Abstract

An applicator device for abutment by or attachment to a reciprocating mechanism of a viscous fluid material printing machine, the applicator device including: a body having a through passage with an upper, fluid inlet extending along the body and a lower, fluid outlet extending along the body; an elongate, horizontally-extending reservoir for fluid material formed with or detachably mounted on an upper side of the body and being in fluid communication with the inlet of the body; and a displaceable piston extending in the reservoir for displacing fluid material out of the reservoir into the inlet of the body and to the outlet of the body, with the piston being actuable from above by the reciprocating mechanism of the printing machine so as to be displaceable thereby and the applicator device being without and not requiring any other separate motive power source or pipe ducting means for such displacement.

1. An applicator device for abutment by or attachment to a reciprocating mechanism of a viscous fluid material printing machine, the applicator device being for applying a viscous fluid material to a surface therebeneath and comprising:
 a body having a through passage with an upper, fluid inlet extending along the body, a lower, fluid outlet extending along the body and pressure reduction means between the inlet and the outlet of the body for reducing the pressure of the fluid material; 
 a sealing gasket or foil for peripherally sealing the outlet of the body against a stencil on being pressed thereagainst; 
 an elongate, horizontally-extending reservoir for fluid material formed with or detachably mounted on an upper side of the body and being in fluid communication with the inlet of the body; and 
 a displaceable piston extending in the reservoir for displacing fluid material out of the reservoir into the inlet of the body and, via the pressure reduction means, to the outlet of the body, with the piston being actuable from above by the reciprocating mechanism of the printing machine so as to be displaceable thereby and the applicator device being without and not requiring any other separate motive power source or pipe ducting means for such displacement. 
 
   
   
     2. A device as claimed in  claim 1 , further comprising:
 first and second pusher members, each being connectable to or abuttable by the reciprocating mechanism of the printing machine so as to be alternately upwardly/downwardly operatively displaceable at the end of each horizontal displacement and act on the piston. 
 
   
   
     3. A device as claimed in  claim 2 , wherein the pusher members each act via a pressure distribution portion thereof, which spreads the pressure across the piston transverse to the longitudinal extent thereof, such as to minimize any backwards/forwards tilting movement of the piston. 
   
   
     4. A device as claimed in  claim 3 , wherein the pressure distribution portions have a complementary shape so as to interdigitate. 
   
   
     5. A device as claimed in  claim 4 , wherein the pressure distribution portions have a castellated outline. 
   
   
     6. A device as claimed in  claim 2 , wherein the pusher members are adapted to provide for an alternate tilting displacement of the piston along the length thereof such as at least to maintain the characteristics of the fluid material. 
   
   
     7. A device as claimed in  claim 1 , wherein the body comprises an elongate plate member including an elongate slot as the pressure reduction means between the inlet and the outlet of the body. 
   
   
     8. A device as claimed in  claim 7 , wherein the reservoir is securably mountable on an upper side of the plate member, and includes at least one outlet in fluid communication with the slot. 
   
   
     9. A device as claimed in  claim 7 , wherein the reservoir is provided by a continuous upstanding wall on the plate member extending around the slot to contain fluid material. 
   
   
     10. A device as claimed in  claim 1 , further comprising:
 at least one sliding or slidable spacing member having a planar lower face disposed to the bottom of the body and extending along opposite sides of the sealing gasket or foil, which gasket or foil includes a sealing edge which, when not being biased by the counter-pressure of a stencil, extends beneath the lower face of the at least one spacing member such that the at least one spacing member in part determines the amount the sealing edge is displaced upwardly against resilient means when the sealing edge and the at least one spacing member are supported on a stencil. 
 
   
   
     11. A device as claimed in  claim 1 , wherein the sealing gasket or foil is formed from a sheet of flexible material and has an uninterrupted or continuous, non-apertured outer part extending around the periphery of the outlet of the body and surrounding an apertured inner region. 
   
   
     12. A device as claimed in  claim 11 , wherein a continuous resilient ring is located between the body and the sealing gasket or foil extending around the outlet of the body so as in use to form a seal between the body and the sealing gasket or foil. 
   
   
     13. A device as claimed in  claim 1 , wherein the body, the reservoir and the sealing gasket or foil are integrally formed. 
   
   
     14. A device as claimed in  claim 13 , wherein the body includes at least one opening as the pressure reduction means which has a peripheral side formed of flexible material and extending downwardly such as to define a sealing surface which extends as an uninterrupted or continuous, non-apertured outer portion around the periphery of the at least one opening. 
   
   
     15. A solder paste stencil printing machine including a reciprocating mechanism in combination with an applicator device as claimed in  claim 1 , wherein the reciprocating mechanism is operative to exert a pressure and driving force which acts both horizontally to reciprocate the applicator device over the surface of the stencil and apply a downward pressure on the piston and the solder paste thereunder so as to provide the pressure to maintain the sealing gasket or foil in sealing contact with the stencil therebeneath and cause the solder paste to be discharged from the reservoir and through apertures in the stencil onto a circuit board or other electronic component or substrate therebeneath. 
   
   
     16. A combination as claimed in  claim 15 , wherein the reciprocating mechanism includes first reciprocating means for effecting reciprocating displacement of the applicator device in a horizontal or substantially horizontal direction and second reciprocating means for effecting vertical or other upward/downward displacement of the piston of the applicator device, preferably by at least one pusher member of the applicator device. 
   
   
     17. An applicator device as claimed in  claim 1  in combination with an adaptor device for enabling the applicator device to be acted upon by at least one vertically or substantially vertically displaceable pressing member of a viscous fluid material screen printing machine, the adaptor device comprising:
 a piston-pressing member locatable on the piston of the applicator device; a pressure-receiving member which is to be acted upon directly or indirectly by the at least one pressing member of the printing machine; and 
 at least one one-way movement enabling device connecting the piston-pressing member and the pressure-receiving member such as normally only to permit upward movement of the pressure-receiving member relative to the piston-pressing member, wherein, with downward displacement of the pressure-receiving member, the piston-pressing member is displaced downwardly together with the pressure-receiving member such as to urge fluid material contained within the reservoir of the applicator device downwardly and out of the reservoir of the applicator device, and the pressure-receiving member being biased away from the piston-pressing member so as to be displaced upwardly to a raised position following each downward displacement thereof. 
 
   
   
     18. A combination as claimed in  claim 17 , wherein a surface of the pressure-receiving member which is engaged by the at least one pressing member of the printing machine is of or displaced to a height such that, in operation, the required downward displacement of the at least one pressing member of the printing machine does not exceed a maximum displacement of the at least one pressing member of the printing machine as permitted in normal operation of the printing machine without interruption. 
   
   
     19. A combination as claimed in  claim 17 , wherein the pressure-receiving member includes at least one aperture, and the piston-pressing member includes at least one projection which extends through the at least one aperture in the pressure-receiving member, with the at least one projection acting to space the piston-pressing member from the pressure-receiving member and including an enlargement which limits the extent to which the piston-pressing member and the pressure-receiving member can be biased apart. 
   
   
     20. A combination as claimed in  claim 19 , wherein the piston-pressing and pressure-receiving members are separable when changing the applicator device. 
   
   
     21. A combination as claimed in  claim 17 , wherein the at least one one-way movement enabling device is a ball-lock device which includes an annular tapered section and locking balls which lock with the tapered section when the pressure-receiving member is biased downwardly relative to the piston-pressing member and enable movement when the pressure-receiving member is raised relative to the piston-pressing member. 
   
   
     22. A combination as claimed in  claim 21 , wherein the ball-lock device includes a ball displacement cap and is releasable by screwing down the ball displacement cap to displace the locking balls downwardly such as to disengage the locking balls from the tapered section and, where the locking balls are so disengaged, the pressure-receiving member can be raised or lowered relative to the piston-pressing member. 
   
   
     23. A combination as claimed in  claim 17 , wherein the piston-pressing member is an elongate member which is coextensive with the piston of the applicator device and the connection between the piston-pressing member and the piston guides the piston-pressing member such that any tendency for the piston to tilt is at least reduced. 
   
   
     24. An applicator device as claimed in  claim 1  in combination with an adaptor device for enabling the applicator device to be acted upon by at least one vertically or substantially vertically displaceable pressing member of a viscous fluid material screen printing machine, the adaptor device comprising:
 a pressure-receiving member which is to be acted upon directly or indirectly by the at least one pressing member of the printing machine; and 
 a piston-pressing member which is locatable on the piston of the applicator device and coupled to the pressure-receiving member such as to be moved downwardly together with the pressure-receiving member to cause the piston to be displaced downwardly and urge fluid material contained within the reservoir downwardly therefrom; 
 wherein a surface of the pressure-receiving member which is engaged by the at least one pressing member of the printing machine is of or displaced to a height such that, in operation, the required downward displacement of the at least one pressing member of the printing machine does not exceed a maximum displacement of the at least one pressing member of the printing machine as permitted in normal operation of the printing machine without interruption.